The invention relates to a separating device in an oil circuit of a motor vehicle, comprising a pressure-generating oil pump and an oil tank, for separating an oil stream loaded with gas into one partial stream with little air and a partial stream containing air with a curved guide rib, by means of which an oil stream introduced tangentially on the inside of it is diverted/set in rotation.
Oil for cooling and/or as a lubricant is generally used in circulation in a circuit, especially in the motor vehicle area. In this process, starting from an oil reservoir/tank, oil is pumped by means of an oil pump through supply lines to the site of action and pumped back to the tank through return lines, whereby the pump(s) can be arranged either between the tank and the site of action and/or between the site of action and the tank. Since air is normally also present, in addition to the oil in the circuit, a loading of the liquid oil with gaseous air is unavoidable due to the (circulation) movement so the oil more or less foams.
Oil loaded with air is greatly restricted in its effects with respect to lubrication and/or heat transporting capability, resulting in the occurrence of increased wear and thus a reduced service life, e.g., of an internal combustion engine. For this reason, an attempt is made on one hand to prevent loading the oil with air by using an appropriate oil movement, in addition oils are used that have a low tendency to foam. On the other hand it is still necessary to again degasify foamy oil loaded with air.
In this context, various methods and devices have become known for providing oil that is free of air. DE 26 23 238 C2, for example, describes a device for providing lubricant oil that is essentially free of air, whereby a so-called cyclone separator is used as the central separating element. According to DE 36 23 238 C2 the oil loaded with air is introduced by way of an inlet opening into the cyclone separator, by the use of one part of the oil pressure energy a separation occurs into a partial air stream with little air that escapes at the bottom and peripherally and a partial stream containing air that escapes at the top and/or centrally.
These types of air separators are known in principle, but they form a separate component that takes up construction space and involves a certain amount of expense for manufacturing and installation.
In this context, reference is made to DE 1 903 295 A1 and DE 2 005 594 A1 that show arrangements according to the preamble of claim 1. In each case, the air separator is an independent, very complicated component designed with a number of individual elements and mounted on the inside of the oil tank with great effort.
As a result of DE 1 903 295 A1, connecting ribs for connecting the bell to the supply tank are also necessary, as is a separate passage of the return line through the wall of the supply tank. According to DE 2 005 594 A1, the bell of the separately-formed defoaming device is fastened, using a screw, in a complicated way on a removable cover of one wall of the supply tank and thus not integrated. In addition, a passage for the return line that is separate from the defoaming device is necessary.
Thus the object of the invention is to provide a separating device for separating air from oil in an oil circuit with low manufacturing effort, low cost and reduced construction space.
According to the invention, the object is achieved by a separating device which is an integral component of the oil tank.
According to a preferred embodiment of the invention, an oil tank comprises a reservoir and a cover formed as an upper shell, and for formation of the separating device the cover itself is designed appropriately. The cover of the separating device is effectively manufactured of a plastic here, like polyamide.
It is especially advantageous if the oil stream introduced is shaped so that it is flat, by means of an appropriately designed intake device, so that it acts on a broad area of the guide rib.
It has proven to be very effective if the partial stream with little air is carried away downward and/or peripherally and the partial stream carrying air is carried away toward the top and/or centrally, in this process a dome that is open toward the bottom and extends into the tank radially on the inside, concentrically to a guide rib, is provided for return of the partial stream containing air. This dome makes possible for the carrying away to take place in a low-rotation space with little air movement.
Because of the very compact construction of the separating device, it is especially suitable for use in connection with an oil tank, especially in a motorcycle.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.